The quality of public housing is a key determinant of health among low-income populations. Substandard housing – where mold, pest infestations, fire hazards, or other health risks are present – is associated with a wide range of health problems, including respiratory infections, asthma, lead poisoning and mental health issues. Nor is illness the only concern: Each year millions of Americans are injured, and tens of thousands killed, by accidents in and around their homes that may be linked to housing conditions. Access to safe and affordable housing is not just an economic issue, but a major public health issue.

However, much of the public housing in the United States is in disrepair – unhealthy, unsafe, even uninhabitable. The federal Department of Housing and Urban Development (HUD) has been working for many years to fix the problem, but with the cost of bringing public housing up to standard estimated at more than $20 billion nationwide, it’s a daunting task. (It doesn’t help that HUD’s budget, especially the portion for maintenance and renovation, which was inadequate in the first place, has been repeatedly slashed for the last 30 years.)

In 2011, Congress passed the Rental Assistance Demonstration Project (RAD), a pilot program providing for the purchase and renovation of some 60,000 units of public housing by nonprofit organizations or private entities. A linchpin of the program is the requirement that for 15 to 20 years the new owners must continue to make the housing available to the same populations that currently live there.

Recently San Francisco, where soaring rents are forcing increasing numbers of low- and medium-income renters out of the city, was awarded a grant from HUD to rehabilitate its public housing stock – enough to renovate three-fourths of all units. In order to qualify for renovation, the units must be sold to private or nonprofit owners who get tax credits. The units then become Section 8 voucher properties (where low-income tenants pay 30 percent of their rent and vouchers make up the difference to the landlord), and the owners sign a contract to keep them as such for 20 years.

Human Impact Partners’ HIA of the RAD project predicted that the program would lead to improved housing quality, decreased stress among residents and decreased crime around renovated housing. But the devil is in the details. We also predicted that RAD, if not done well, could lead to poor health due to potential evictions, displacement, lack of authentic resident inclusion in decision-making, and stress from not knowing whether one’s housing is secure over the long term.

Here’s what we believe San Francisco must do to avoid those potential negative impacts:

Ensure that clear standards are set for protecting residents from evictions, displacement and changes in affordability.

Require new management to have a long-term plan to preserve the housing stock.

Create funding for services, support and protections for those typically hard to house, such as the elderly, large families, people with disabilities, those who have been arrested or incarcerated, and those with poor credit histories.

Create an oversight committee of leaders of resident organizations in the housing sites, housing advocates and elected officials.

Develop metrics that truly measure determinants of health to understand how RAD affects health over time.

Affordable housing is not only vital for low-income populations, but to the community at large. We’ve seen what happened when the mental health system that helped those who could not live without support was dismantled. Homelessness and incarceration shot through the roof. We don’t want that to happen if public housing goes away. The bottom line: We just aren’t sure that the RAD program offers enough protection to ensure that private interests wouldn’t eventually win out over the public good.

Think about it: You’re a developer who can afford to buy hundreds of units of public housing, get tax breaks from the government for improving them. All you have to do is agree that for 15 to 20 years you will keep them available for low-income populations. After that, you must consider keeping them available, but you’re free to sell them at market rates. In markets such as San Francisco, where even modest units have no shortage of takers eager to rent or buy at prices unthinkable until recently, would you think about public health, or your own opportunity to profit?

Policymakers must consider ways to require or incentivize the continued availability of affordable units. Policymakers who want to consider health and quality of life for their most vulnerable residents must assure that safe, well-maintained housing continues to be available for low-income residents.

Kim Gilhuly, MPH, is a program director for Human Impact Partners, a nonprofit based in Oakland, Calif., that studies the health and equity implications of public policy.